The wiring in the trunk lid will cause the lock and license plate light to not work, but it won't affect brake lights which are on the car body.
e36 tail lights are also prone to burn through the traces when the sockets get corroded. My daughter pulled off her tail light and soldered shut the holes in the trace where the socket contact touches. Holding so far a year later, but eventually she will get new tail lights since hers are original and are pretty discolored.